The present invention relates to current limiting, and in particular, to a method and circuit for over-current protection.
Current limit protection is very important in power supply systems. In pulse width modulated (PWM) switching power supply systems, excessive inductor current may cause thermal damage. Additionally, the excessive current may cause the inductor to become saturated and cause catastrophic failure. For example, the switches of the switching power supply may be permanently damaged. Limiting the current protects power supply system components and may improve overall system reliability.
Conventional methods of current limit protection for switching power supply systems may include detecting the current. During the periodic detecting of the current, the switch may incrementally increase the inductor current. This may cause a run-away condition in which the inductor becomes saturated and the over-current causes system failure.
Thus, there is a need for improved over-current protection. The present invention solves these and other problems by providing method and circuit for over-current protection.